Pump

ABSTRACT

A vacuum pump has at least one side passage pump stage which comprises a side passage bounded by at least one stator element and having a coolant circuit for cooling the vacuum pump with a coolant, wherein the coolant circuit has at least one coolant passage for the side passage pump stage which is bounded at least regionally by the stator element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a pump having at least one side passage pump stage which comprises a side passage bounded by at least one stator element.

The invention generally relates to the sector of pumps and in this respect in particular to the sector of vacuum pumps. The invention is not restricted to vacuum pumps. All statements relating generally to pumps, however, also apply to vacuum pumps.

2. Description of the Prior Art

Pumps, in particular vacuum pumps, are used in different technical processes, for example in semiconductor manufacture, to convey gaseous media away out of a volume to be evacuated and in particular to produce a vacuum required for the respective process. In addition to high-vacuum pump stages such as Holweck pump stages or turbomolecular pump stages, side passage pump stages are used which, on the one hand, are suitable for producing a pure vacuum having a low end pressure and which are simultaneously able to compress the conveyed media to a high output pressure and in individual cases even directly down to atmospheric pressure. A vacuum pump having a side passage pump stage typically additionally comprises a motor for the rotating driving of a rotor element of the side passage pump stage as well as drive electronics for controlling the motor.

A disadvantage in known vacuum pumps of the initially named kind is that their actual performance data as a rule remain well behind the performance data theoretically to be expected and the performance behavior of the vacuum pumps deteriorates over time. The vacuum pumps have to be serviced relatively frequently and have a restricted operating life overall, whereby the economy of the known vacuum pumps is reduced. The maintenance susceptibility and failure susceptibility of the vacuum pumps can be due to the high temperatures which occur in the operation of the vacuum pumps and which result in the medium term and in the long term in an impairment of the functionality of the temperature-sensitive pump components due to the accompanying thermal load.

It is therefore the object of the invention to provide a pump, in particular a vacuum pump, which has a high performance and simultaneously a reduced susceptibility to maintenance and failure, which can be operated in the long term and reliably without any restriction of its functionality and which has a high operating life.

SUMMARY OF THE INVENTION

The object of the invention is achieved by providing a pump that comprises at least one side passage pump stage which has a side passage bounded by at least one stator element. The pump furthermore comprises a coolant circuit for cooling the pump with a coolant, wherein the coolant circuit has at least one coolant passage for the side passage pump which is bounded at least regionally by the stator element.

It was recognized in accordance with the invention that the heat generation caused in the region of the side passage pump stage by its pumping effect results in known pumps in a deterioration of the operating properties of the pump, whereby, on the one hand, the performance properties of the pump are impaired and, on the other hand, a substantial load on the pump components occurs in their operation which increases the susceptibility to maintenance and failure of the pump and which reduces their operating life to be expected.

The thermal energy caused by the pump mechanism of the side passage pump stage is efficiently directly led off through the coolant circuit with the coolant passage which is bounded by the at least one stator element of the side passage pump stage so that an excessive heating and thermal load of the pump which are caused thereby, which deteriorate the performance behavior and which reduce the service life to be expected of the pump are avoided.

A pump is thus provided whose performance behavior at least approximately corresponds to the theoretically expected power capability and which achieves a high reliability in operation and a high operating life.

In accordance with an advantageous embodiment, the coolant circuit is configured for cooling at least one further component of the pump. The performance behavior of the pump can thereby be even further improved and its operating life can be even further increased. The further component can in particular be a motor which in particular serves for the rotating driving of a rotor element of the side passage pump stage or it can be drive electronics which are in particular configured for controlling the motor which is preferably configured as an electric motor. The drive electronics can also serve for the evaluation of signals which are delivered by sensors of the pump, e.g. by a temperature sensor explained below. These components likewise generate substantial heat quantities in the operation of the pump and a controlled leading off of said heat quantities can improve the operating properties of the pump. The further component can furthermore be a high vacuum pump stage such as a Holweck pump stage, a turbomolecular pump stage, a Gaede pump stage, a Siegbahn pump stage or a cross-thread pump stage which can be provided in addition to the side passage pump stage and whose operating behavior can likewise be improved by the cooling. In this respect a substantial improvement of the operating behavior of the pump can be achieved overall with a small effort by the use of a common coolant circuit for cooling the side passage pump stage and the at least one further component. The further component can also be a housing of the pump.

The further component can also comprise a bearing plate of the pump. Such a bearing plate can be arranged, for example, in the region of a roller element bearing of the pump which a rotor shaft of the pump at which the rotor element of the side passage pump stage is arranged is rotatably supported at the pump housing. The bearing plate can be configured to fix an outer ring of the roller element bearing to the housing of the vacuum pump in a manner fixed against displacement in the direction of the axis of rotation. The bearing plate can in this respect in particular be fixedly screwed to the stator element of the side passage pump stage. In this embodiment, a high thermal coupling of the bearing plate with the stator element results so that the cooling of the side passage pump can be assisted by the cooling of the bearing plate and the cooling can thus be improved overall. Two bearing plates of the pump which are e.g. associated with different roller element bearings of the pump can also be able to be cooled by the coolant circuit.

Two or more different further components and in particular all of the above-named different further components can also be able to be cooled by the coolant circuit.

In accordance with an advantageous embodiment, the coolant circuit comprises a further coolant passage for the further component. A direct cooling of the further component can be effected by such a further coolant passage. The respective coolant passage can for this purpose be bounded at least regionally by the respective component. It is generally understood by “bounded at least regionally” in the present disclosure that the coolant passage is bounded over at least a part of its preferably closed flow cross-section by the respective element. In principle, the respective coolant passage can also be bounded over its total flow cross-section by the respective element.

It is preferred in the case of the drive electronics if the coolant passage for the drive electronics is bounded at least regionally by a plate or cooling plate, in particular a thermally conducting and/or metallic plate or cooling plate, on which the drive electronics are fastened by a preferably thermally conductive connection.

The further coolant passage can be connected in series or in parallel in a coolant conducting manner to the coolant passage for the side passage pump stage. The coolant flow and the cooling effect effected by it can thereby be directly adapted to the demands of the side passage pump stage and of the respective further component or components. The pump components to be cooled can in this respect be arranged along the different coolant passages such that a cooling effect corresponding to the respective demands is achieved overall.

For cooling a bearing plate, a coolant passage can be provided which is bounded at least partly by the bearing plate and which is preferably connected in a coolant conducting manner to a coolant passage for the side passage pump stage. It is made possible by the provision of a coolant passage which is bounded by a bearing plate or which passes through it and which is connected to a coolant passage for the side passage pump stage to realize in a simple constructive manner a coolant passage for the side passage pump stage which extends over substantially the total length of the side passage of the pump stage and is arranged in direct proximity to the side passage and which is simultaneously accessible from the outside via the bearing plate and can thus be integrated in a simple construction manner into the coolant circuit.

Both the motor and the drive electronics are each preferably cooled by a coolant passage which is bounded at least regionally by the motor or by a cooling plate for the drive electronics respectively, with the passage for the motor and the passage for the drive electronics preferably being connected to one another in series in a coolant conducting manner.

In accordance with an embodiment, a coolant conducting serial connection is provided between a first coolant passage for the side passage pump stage and for the high vacuum pump stage and a second coolant passage for the drive electronics and for the motor. The second coolant passage preferably comprises a coolant passage which is bounded at least regionally by a cooling plate for the drive electronics and a coolant passage which follows it in the coolant flow direction and which is bounded at least regionally by the motor. The first coolant passage preferably follows the second passage in the coolant flow direction and is bounded at least regionally by the side passage pump stage. The high vacuum pump stage can either have its own coolant passage and bound it at least regionally or it can be able to be cooled in the manner described in the following indirectly via the coolant passage for the side passage pump stage. A modification of the above embodiment provides that the coolant passage for the motor is arranged in front of the coolant passage for the drive electronics in the flow direction of the coolant.

A further embodiment provides that a coolant passage for the motor and for the drive electronics, on the one hand, and a coolant passage for the side passage pump stage and for the high vacuum pump stage, on the other hand, are connected in parallel to one another.

The further component, in particular the high vacuum pump stage, can also be able to be indirectly cooled in that it is connected in a thermally conducting manner to the at least one stator element of the side passage pump stage or of a further, third pump component, which is in turn directly cooled by the coolant circuit, i.e. which at least regionally bounds a coolant passage of the coolant circuit or which is likewise indirectly cooled by the coolant circuit.

In particular in the event of a serial connection of two coolant passages, the flow cross-sections of the two passages and thus their hydraulic conductivities are preferably adapted such that a desired division of the coolant to the two passages results.

In accordance with an embodiment, at least one diaphragm, in particular an adjustable diaphragm, is provided in the coolant circuit and bounds a flow cross-section for the coolant. The diaphragm can in this respect in particular be arranged in one of at least two coolant passages connected in parallel. The hydraulic conductivity of the respective passage can then be flexibly adapted to the respective conditions.

A further embodiment provides that at least one temperature sensor is provided for measuring the temperature of the side passage pump stage. It is thereby made possible to monitor the temperature of the side passage pump stage during operation and e.g. to control the operation of the side passage pump stage and/or to control the coolant circuit in dependence on the measured temperature of the vacuum pump so that the side passage pump is always operated in a favorable temperature range. The at least one temperature sensor is preferably arranged between the coolant passage and the side passage of the side passage pump stage and/or in the proximity of a gas outlet of the side passage pump stage. A particularly direct and thus meaningful measurement of the temperature of the side passage stage is thus achieved. The temperature sensor can also be arranged at a bearing mounting or at a bearing plate of a pivot bearing of the pump and can measure the temperature of the bearing mounting or of the bearing plate, with the bearing mounting and/or the bearing plate being able to be cooled by the coolant circuit.

The coolant passage preferably extends over at least approximately the total length of the side passage. A particularly effective removal of the heat produced in the side passage is thereby ensured since the heat is directly led off everywhere. The coolant passage can be bounded at least regionally by the at least one stator element at least approximately along its total length.

The coolant passage can extend over at least 60%, preferably at least 75% and particularly preferably at least 90%, of the angular region which is defined with respect to an axis of rotation of the side passage pump stage, which is covered by the side passage and which can comprise a full rotation of 360°. The side passage and/or the coolant passage in this respect preferably extends/extend in the manner of a circumferential line at least regionally about the axis of rotation.

A particularly effective cooling of the side passage pump stage is achieved when the coolant passage is spaced apart from the side passage in the radial direction toward the outside with respect to the axis of rotation of the side passage pump stage at least over a part of its length.

A particularly preferred embodiment provides that the coolant passage is arranged in direct proximity to the side passage over at least approximately its total length. The efficiency of the cooling of the side passage pump stage is thereby even further increased. The coolant passage in this respect preferably has a shortest spacing from the side passage over its length which amounts to at most 50%, preferably at most 25%, and particularly preferably at most 15%, of the maximum spacing of the side passage from the axis of rotation.

A particularly simple design of the pump results when the side passage and/or the coolant passage is bounded over at least a part of its length by at least two stator elements which preferably contact one another and are connected to one another, in particular by a screw connection. A groove which corresponds to the side passage can then be provided in the stator element and/or a groove which corresponds to the coolant passage and which forms, together with a further groove or with a flat surface of the respective other stator element, the boundary for the side passage or for the coolant passage.

The two stator elements can contact one another substantially areally in a region adjacent to the respective side passage or coolant passage, whereby a connection sealing the coolant passage can be provided between the two stator elements. A stator element can respectively be designed substantially in disk shape, with the disk plane preferably being oriented substantially perpendicular to the axis of rotation of the side passage pump stage and with the surface of the disk bounding the respective side passage or coolant passage preferably being formed by a flat side of the disk and the two disks in particular contacting one another and being connected to one another at their flat sides.

A sealing element, in particular an elastic sealing element, can be provided between the at least two stator elements for an even better sealing, in particular of the coolant passage, and the two stator elements can sealingly contact the sealing element. The sealing element can be configured e.g. as an O ring which preferably sealingly connects a closed ring-shaped surface of the one stator element to a closed ring-shaped surface of the other stator element to mutually seal the coolant passage and the side passage, which can be arranged on different sides of the ring-shaped surfaces. The O ring can be arranged between the coolant passage and the side passage in the radial direction with respect to the axis of rotation. At least one further O ring can also be present which seals the coolant passage and/or the side passage with respect to the region outside the stator elements bounding the two passages.

In accordance with an advantageous embodiment, the coolant inlet of the coolant passage is arranged in the proximity of a gas outlet of the side passage pump stage and/or the coolant outlet of the coolant passage is arranged in the proximity of a gas inlet of the side passage pump stage. The cooling effect is thereby adapted to the heat development in the side passage pump stage such that a substantially homogeneous temperature distribution is adopted everywhere in the operation of the pump and locally highly increased temperatures are avoided.

A particularly strong heat development, which can be compensated by the arrangement of the coolant inlet in this region and by the associated greater cooling effect, namely occurs in the proximity of the gas outlet of the side passage pump stage due to the high gas pressure and the increased friction. The region of the coolant outlet which provides a smaller cooling effect is accordingly utilized for cooling the region of the gas inlet in which a smaller heat development occurs due to the smaller gas pressures. In principle, the coolant inlet and/or the coolant outlet can, however, also be arranged at another site than the site respectively given above.

The direction in which the coolant flows about the axis of rotation of the side passage pump stage in the coolant passage in the operation of the pump can be opposite to the direction in which the gas flows through the side passage of the associated side passage pump stage. A cooling effect is thereby achieved which effectively compensates the gradient of the heat generation along the side passage which is caused by the greater heat generation in the region of the gas outlet and the smaller heat generation in the region of the gas inlet. In principle, the coolant and the gas can, however, also flow about the axis of rotation of the side passage pump stage in the same direction.

In accordance with an advantageous embodiment, the pump comprises a plurality of side passage pump stages which each comprise a side passage bounded by at least one stator element. A plurality of side passage pump stages, and in particular all side passage pump stages, can in this respect be configured in accordance with east one of the advantageous embodiments described above with respect to the at least one side passage pump stage. The achievable pump power and the achievable minimal end pressure of the vacuum and the maximum output pressure of the pump can be improved by the provision of a plurality of side passage pump stages. The side passage pump stages can in this respect be connected to one another in a gas conducting manner in series and/or in parallel. A high performance pump can in principle comprise one or two or more than two mutually connected side passage pump stages.

The coolant circuit preferably respectively comprises at least one coolant passage for each side passage pump stage, with the coolant passages each being bounded by the stator element which bounds the side passage of the respective side passage pump stage. An effective cooling of the stator elements of all side passage pump stages is thereby ensured.

The side passages of different side passage pump stages can in this respect be arranged following one another in the radial direction and/or in the axial direction with respect to the axis of rotation of the at least one side passage pump stage. A side passage can in this respect, as described above, be bounded by at least two stator elements, in particular of disk shape.

A stator element can also bound a plurality of different side passages and thus represent a common stator element for more than one side passage pump stage. A coolant passage bounded by the stator element can accordingly also represent a common coolant passage for more than one side passage pump stage. A stator element can also bound a plurality of different coolant passages which are each associated with a respective one of a plurality of side passages bounded by the respective stator element.

At least one disk-shaped stator element can, for example, have a respective groove bounding a side passage at its two flat sides disposed opposite one another and/or the stator element can have a respective groove bounding a coolant passage for a side passage pump stage at both sides. This represents a particularly simple construction variant with which in particular a plurality of side passage pump stages can be realized which follow one another in the direction of the axis of rotation. The two side passages and/or coolant passages bounded by the stator element can in this respect be connected to one another in a gas conducting or coolant conducting manner by a corresponding connection passage formed in the stator element.

At least two coolant passages of different side passage pump stages are preferably connected to one another in a coolant conducting manner. The coolant passages can in this respect be connected in series to one another so that they are flowed through in order by the coolant. The coolant passages can also be connected to one another in parallel and can be flowed through by the coolant in parallel. With a parallel connection of the coolant passages, the flow in the two coolant passages can be regulated respectively independently, for example by corresponding adaptation of the flow cross-section and/or by the arrangement of a diaphragm in a respective coolant passage so that the cooling of the individual side passage pump stages can be flexibly adapted to their thermal load, for example to adapt the cooling to different load cases, in particular to the end pressure to be produced or to the incurred gas load.

In accordance with an advantageous embodiment, at least two coolant passages of different side passage pump stages which in particular follow one another directly in the axial direction or in the radial direction extend from their respective coolant inlet in opposite directions about an axis of rotation of the side passage pump stages to their respective coolant outlet. It is thereby made possible to arrange the different coolant passages so that they overlap with respect to the angular regions covered by them with respect to the axis of rotation of the side passage pump stage and an angular offset between the inlets and the outlets of mutually following coolant passages is avoided. A particularly simple construction arrangement is thereby achieved since the different coolant passages or the stator elements bounding them can have substantially an identical design and can be arranged congruent with one another.

The coolant passages can, for example, each have an extent oriented about the axis of rotation of the side passage pump stage and can in this respect each approximately cover the total angular region with respect to the axis of rotation of the side passage pump stage, with a relatively small angular range not being able to be covered by the passage and thus being able to remain free between the coolant inlet and the coolant outlet. It can in particular be achieved in this case by the above-described embodiment with alternating flow directions of the coolant that the angular regions remaining free between the inlets and the outlets of different coolant passages overlap at least in part. The overlapping angular regions can then be used for further components of the pump or of the coolant circuit.

For example, a return passage of the coolant circuit can be provided which extends through a plurality of stator elements which bound the side passages of the side passage pump stages. The return passage for the coolant can in particular be arranged in the above-described overlapping angular region which remains free between the inlets and the outlets of the different side passage pump stages.

Within the framework of the present description, a coolant circuit is understood both as a closed circuit for the coolant and as a section for the coolant between a coolant inlet and a coolant outlet which can be completed by a corresponding connection of the inlet and of the outlet to one another to form a closed circuit. The coolant circuit can, in particular in the case of a closed coolant circuit, comprise a coolant pump with which the coolant can be driven in the circuit and/or a cooling unit or a heat exchanger with which the coolant can be cooled. The coolant pump and/or the heat exchanger can be configured as part of the pump or can be able to be connected externally to a corresponding cooling inlet and cooling outlet of the pump.

In accordance with an advantageous embodiment, the coolant circuit is coupled in a heat exchanging manner via at least one heat conducting element to a further coolant circuit. The cooling of the coolant circuit which comprises the coolant passage bounded by the stator element of the side passage pump stage and which is also called the primary circuit in this respect takes place via the heat conducting element by the further coolant circuit which is also called the secondary circuit. The further coolant circuit can e.g. be connected via a coolant inlet and a coolant outlet of the pump to an external coolant pump and/or to an external coolant unit or heat exchanger. The heat exchanging element can in particular be formed by a plate on which the drive electronics are arranged and which exchange the heat between the two coolant circuits and for this purpose preferably at least regionally bounds a respective coolant passage of both circuits. This cooling plate can have a relatively large surface and thus ensure an effective heat exchange. In principle, a liquid-gas heat exchanger, e.g. a water-air heat exchanger, can also be provided which effects a heat exchange between the liquid coolant and a gas, e.g. the environmental air, present outside the primary circuit or secondary circuit and in particular outside the pump for cooling a liquid coolant in the primary circuit or a liquid coolant in a present secondary circuit.

The above embodiment has the advantage that the primary circuit can be configured as a closed circuit formed as part of the pump, for example, with a corresponding coolant pump, without a coolant unit or an excessively large heat exchanger simultaneously having to be integrated into the pump. A corrosion-resistant coolant can e.g. be used in the primary circuit in this respect and is particularly suitable for a direct cooling of the affected components without e.g. there being a risk of leak losses or of the accidental use of an unsuitable coolant due to an external link of the coolant circuit. The secondary circuit can in contrast be operated with water as the coolant which can be supplied from outside the pump so that coolant losses in the subsequent region of this circuit are not problematic.

In accordance with an embodiment, the at least one stator element comprises at least regionally, and in particular in the region of a surface bounding the coolant passage, a material which is a material which can be produced by casting or is a cast or metallic material and/or is aluminum or an aluminum alloy. Manufacturing costs for the stator element can thereby be reduced. Alternatively or additionally, a bearing plate or a surface of the bearing plate bounding a coolant passage of the coolant circuit can be formed from such a material.

The coolant of the coolant circuit for the side passage pump stage, which can be formed by a primary circuit as described above, is preferably liquid. The coolant is preferably a coolant which is corrosion-resistant with respect to the material of the stator element which can be one of the above-named materials. For example, the coolant can comprise or consist of glycol or a glycol mixture, an oil, in particular a polychlorinated biphenyl (PCB), a liquid sodium such as NaK-78 or an ethanol. The coolant can also comprise or consist of water depending on the material of the components to be cooled and in particular on the material of the stator element.

If a secondary circuit as described above is provided, it preferably likewise comprises a liquid coolant which in particular comprises or consists of water. The secondary circuit can in principle, however, also comprise a gaseous coolant such as air.

The pump can comprise one or more high vacuum pump stages, with a high vacuum pump stage e.g. being able to be formed by a Holweck pump stage, a turbomolecular pump stage, a Gaede pump stage, a Siegbahn pump stage or a cross-thread pump stage. The one or more high vacuum pump stages are preferably arranged in front of and connected upstream of the side passage pump stage in the flow direction.

A further subject of the invention is a pump having at least one side passage pump stage which comprises a side passage bounded by at least one stator element, having a motor, having drive electronics for the motor and having a coolant circuit for cooling the vacuum pump with a coolant, wherein the coolant circuit comprises at least one first coolant passage for the side passage pump stage and at least one second coolant passage for the motor and/or for the drive electronics.

An excessive heating of the side passage pump and of the motor and/or of the drive electronics which deteriorates the pump behavior or the operating life of the pump can thereby be effectively avoided and a high pump performance as well as a high operating life of the pump can be ensured. The drive electronics can be configured, in addition to the control of the motor, also for evaluating signals which are delivered by sensors of the vacuum pump such as a temperature sensor as described above.

The first coolant passage and the second coolant passage can be connected to one another in a coolant conducting manner in series or in parallel. An interrelated coolant circuit for the named components can thus be achieved which can be realized with small effort, with the cooling effect exerted on the respective components being able to directly adapted to the respective demands by the corresponding serial or parallel coolant conducting connection.

The present invention will be described below by way of example with reference to advantageous embodiments and to the enclosed Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show:

FIG. 1 a schematic view of a vacuum pump in accordance with an embodiment of the invention;

FIG. 2 a schematic view of a vacuum pump in accordance with a further embodiment of the invention;

FIG. 3 a schematic view of a vacuum pump in accordance with a further embodiment of the invention;

FIG. 4 a plane view of a stator element of a side passage pump stage of a vacuum pump in accordance with an embodiment of the invention;

FIG. 5 a schematic view of the coolant flow direction through a plurality of side passage pump stages in a vacuum pump in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a vacuum pump 10 in accordance with an embodiment of the invention in a schematic representation. The vacuum pump 10 comprises a side passage pump stage 12 which has at least one stator element 14, an electric motor 22 for the rotational driving of a rotor element of the side passage pump stage 12, a cooling plate having drive electronics 20 arranged thereon for the motor 22 and a high vacuum pump stage 24.

The pump 10 furthermore comprises a coolant circuit 25 which comprises a coolant inlet 44 accessible from outside the pump 10 and a coolant outlet 46 of the vacuum pump 10 accessible from outside the pump 10, wherein the inlet 44 and the outlet 46 are connected to one another in a coolant conducting manner via coolant passages 18, 26 of the coolant circuit 25. The arrow tips in FIG. 1 characterize the coolant flow direction from the inlet 44 to the outlet 46.

The coolant passage 18 serves for the cooling of the side passage pump stage 12 and is bounded at least regionally by the stator element 14 of the side passage pump stage 12. The high vacuum pump stage 24 can be indirectly cooled via the side passage pump stage 12 to which it is heat conductively connected. The cooling of the high vacuum pump stage 24 can in principle also take place via a bearing plate of the vacuum pump and/or via the housing of the vacuum pump. The coolant passage 26 serves for the cooling of the motor 22 and of the cooling plate having the drive electronics 20 and for this purpose has two longitudinal sections which are connected to one another in a coolant conducting manner in series and of which one is bounded at least regionally by the electric motor 22 and the other is bounded at least regionally by be cooling plate 20. The coolant passage 18 and the coolant passage 26 are each led together in the region of the inlet 44 and of the outlet 46 and are thus connected to one another in a coolant conducting manner in parallel.

FIG. 2 shows a vacuum pump 10 in accordance with a further embodiment of the invention in a schematic representation. The vacuum pump 10 shown in FIG. 2 corresponds to the vacuum pump 10 shown in FIG. 1, wherein in the embodiment shown in FIG. 2 the outlet of the coolant passage 26 for the motor 22 and the cooling plate having the drive electronics 20 are connected in a coolant conducting manner to the inlet of the coolant passage 18 for the side passage pump stage 12 so that the passages 26, 18 are connected to one another in series.

FIG. 3 shows a vacuum pump 10 in accordance with a further embodiment of the invention in a schematic representation. The vacuum pump 10 shown in FIG. 3 substantially corresponds to the vacuum pump 10 shown in FIG. 2, wherein in the embodiment shown in FIG. 3 the coolant circuit 25 is not arranged between a coolant inlet and a coolant outlet of the pump 10. Instead the coolant circuit 25 is configured as a closed circuit and comprises a coolant pump 54 with which the coolant can be driven in the circulation sense marked by the arrow tips in FIG. 3.

The pump 10 additionally comprises a secondary coolant circuit 42 which is accessible from outside the vacuum pump 10 via a corresponding coolant inlet 44 and coolant outlet 46. The secondary coolant circuit 42 comprises a coolant passage 58 bounded at least regionally by the cooling plate 20 for the drive electronics. The coolant circuits 25 and 42 are thus connected to one another in a heat conducting manner via the cooling plate 20 so that the cooling plate 20 serves as a heat exchanger between the two coolant circuits 25, 42. When a coolant source is connected to the inlet 44 and to the outlet 46, the coolant is cooled in the coolant circuit 25 via the coolant plate 20 cooled by the coolant circuit 42 so that the coolant circuit 25 can satisfy its cooling function. Alternatively or additionally, a liquid-gas heat exchanger, e.g. a water-air heat exchanger, could also be provided which effects a heat exchange between the liquid coolant and a gas present outside the circuits 25, 42 for cooling a liquid coolant present in one of the coolant circuits 25, 42 or the cooling plate 20 could be formed as such a heat exchanger.

FIG. 4 shows a stator element 14 of a side passage pump stage of a vacuum pump in accordance with an embodiment of the invention in a plan view. The stator element 14 is configured in disk shape, with the view of a flat side of the disk-shaped stator element 14 being shown in FIG. 4. The stator element 14 comprises a groove which extends in the form of a circumferential line about an axis of rotation 38 of the side passage pump stage oriented perpendicular to the disk plane, which is formed in the flat side, which springs inward into the flat side in the axial direction and whose enclosure bounds a side passage 16. The one longitudinal end of the groove in this respect bounds a gas Inlet 34 of the side passage 16 and the other longitudinal end bounds a gas outlet 36 of the side passage 16.

The stator element 14 furthermore comprises a groove which is likewise formed in the flat side, which springs inward into the flat side in the axial direction and whose enclosure bounds a coolant passage 18 for cooling the stator element 14. The coolant passage 18 extends in parallel to the side passage 16 and accordingly extends likewise substantially in the shape of a circumferential line about the axis of rotation 38. The groove and thus the coolant passage 18 are spaced apart radially outwardly from the side passage 16 at a small spacing. The groove and the coolant passage 18 bounded by its enclosure extend over approximately the whole angular range of 360° with respect to the axis of rotation 38. The one end of the groove bounds an inlet 30 of the coolant passage 16 for the coolant and the other end of the groove bounds an outlet 32 of the coolant passage 16 for the coolant. The coolant inlet 30 is arranged in the proximity of the gas outlet 36 and the coolant outlet 32 is arranged in the proximity of the gas inlet 34. The coolant in the coolant passage 18, on the one hand, and the gas in the side passage 16, on the other hand, thus flow in different directions or in a different sense of rotation about the axis of rotation 38 from their respective inlet to their respective outlet. Alternatively, the coolant in the coolant passage 18 could also flow in the same direction, i.e. in the same sense of rotation as the gas flow in the side passage 16 about the axis of rotation 38, i.e. the coolant can generally flow against the gas flow or with the gas flow. If a plurality of coolant passages are connected behind one another for a plurality of mutually following side passage pump stages, as explained in the following with reference to FIG. 5, the sense of rotation of the coolant flow in the coolant passages can alternate from coolant passage to coolant passage or from side passage pump stage to side passage pump stage.

A return passage 40 is provided in the angular range φ not covered by the coolant passage 18 between the coolant inlet 30 and the coolant outlet 32, said return passage extending through the stator element 14 in the axial direction and serving the return of the coolant.

For forming the side passage pump stage, the stator disk 14 shown in FIG. 4 is connected to a further stator disk not shown in FIG. 4 such that the flat sides of the stator disks contact one another. The further stator disk is in this respect formed complementary to the stator disk shown in FIG. 4 such that the two stator disks together form a coolant passage 18 having a closed cross-section as well as a side passage 16 which has a closed cross-section apart from a peripheral opening via which the rotor element of the side passage pump stage engages into the side passage 16. The two stator elements 14 are fixedly connected to one another via screw bores 52 for this purpose.

A temperature sensor 28 is arranged between the side passage 16 and the coolant passage 18 and serves for measuring the temperature of the side passage pump stage. The temperature sensor 28 can in principle be arranged at any desired point between the side passage 16 and the coolant passage 18 and in particular in the proximity of the gas outlet 36 since there the highest temperatures are present due to the high gas pressure and can be measured directly.

A rotor element, not shown in FIG. 4, of the side passage pump stage is rotationally driven in the direction of the arrow 48 during the operation of the pump. The rotor element can in this respect be arranged at a rotor shaft which can extend through the opening 60 of the stator element 14 provided in the region of the axis of rotation 38. The rotor element preferably has a wreath of blades which extend into the side passage 16.

The side passage 16 in this respect preferably has a cross-section increased with respect to the rotor blades in the region between the gas inlet 34 and the gas outlet 36 and the gas is preferably driven in the manner of a spiral line in the direction of the arrow 48 about the main orientation of the side passage 16 of circumferential line form in the side passage 16 and is compressed in so doing. In the region of the gas outlet 36, the side passage 16 preferably has a cross-section not increased or at most slightly increased with respect to the rotor blades, which can be seen in FIG. 4 with reference to the non-recessed region 50 of the stator element 14 so that the conveyed gas is stripped off in the region of the outlet 36 and is conveyed out of the side passage 16 through the outlet 36.

The pump having the stator element 14 shown in FIG. 14 can comprise a plurality of side passage pump stages which are arranged behind one another in the direction of the axis of rotation 38 and which are formed in accordance with the above description. The coolant passage 18 can be connected in series to the coolant passages of the further side passage pump stages, i.e. the coolant inlet 30 is connected in a coolant conducting manner to the coolant outlet of a preceding pump stage, arranged e.g. in front of the drawing plane of FIG. 4 in the axial direction, and the coolant outlet 32 is connected in a coolant conducting manner to the coolant inlet of a following pump stage, arranged e.g. behind the drawing plane of FIG. 4 in the axial direction. The connections can in this respect be formed by coolant conducting connection passages which extend through the respective stator disk 14 in the axial direction.

The side passage 16 can be connected in series to the side passages of the further side passage stages in that the inlet 34 is connected in a gas conducting manner to the outlet of the preceding pump stage and the outlet 36 is connected in a gas conducting manner to the inlet of the following pump stage. For this purpose, a respective gas conducting connection passage can be provided which extends through a respective stator disk 14 in the axial direction.

All the stator disks 14 of the vacuum pump arranged behind one another in the axial direction preferably each have a coolant return passage 40 as shown in FIG. 4, wherein the coolant return passages 40 are arranged substantially congruent in an aligned manner above one another in the axial direction and together form a coolant return passage oriented in the axial direction and extending through all the side passage pump stages.

FIG. 5 shows a schematic representation of the coolant flow direction through a plurality of side passage pump stages in a vacuum pump in accordance with an embodiment of the invention viewed in the direction of the axis of rotation 38. The vacuum pump can be formed as described above with respect to FIG. 4.

FIG. 5 shows a plurality of coolant passages 18 which are connected to one another in series, which are each associated with a side passage pump stage and which are configured in accordance with the above description of FIG. 4. The coolant passages 18 are shown spaced apart from one another in the radial direction in FIG. 5 and can accordingly be associated with mutually following side passage pump stages in the radial direction. The coolant passages 18 can, however, also follow one another in the axial direction in accordance with the above description of FIG. 4 and can be associated with side passage pump stages mutually following in the axial direction.

The coolant moves through a feed passage 56 which can, for example, lead through a bearing plate or be bounded by it, into the first coolant passage 18. The coolant flows through this coolant passage 18 in a first direction of rotation with respect to the axis of rotation 38 and then moves via a connection passage 62 into the next coolant passage 18 which the coolant flows through in the oppositely directed direction of rotation. In this manner, the coolant flows through all the coolant passages 18, with the flow direction of the coolant alternating from passage 18 to passage 18 until the coolant finally flows out of the last coolant passage 18 into the coolant return passage 48. The coolant return passage 40 extends in the angular region φ not covered by the coolant passage 18 through all stator disks back to a coolant outlet of the vacuum pump. The coolant passage 40 can in this respect likewise lead through a bearing plate of the vacuum pump or be bounded by the bearing plate. 

What is claimed is:
 1. A pump comprising at least one side passage pump stage (12) having a side passage (16) bounded by at least one stator element (14); and a coolant circuit (25) for cooling the pump (10) with a coolant, wherein the coolant circuit (25) has at least one coolant passage (18) for the side passage pump stage (12), said coolant passage being bounded at least regionally by the stator element (14).
 2. The pump in accordance with claim 1, wherein the coolant circuit (25) is configured for cooling at least one further component (20, 22, 24) of the pump (10).
 3. The pump in accordance with claim 2, wherein the component is selected from the group comprising drive electronics (20), a motor (22), a pump stage, a high vacuum pump stage (24), a housing and a bearing plate of the pump (10).
 4. The pump in accordance with claim 2, wherein the coolant circuit (25) comprises a further coolant passage (26) for the further component (20, 22, 24).
 5. The pump in accordance with claim 4, wherein the component is connected in a coolant conducting manner in series or in parallel to the coolant passage (18) for the side passage pump stage (12).
 6. The pump in accordance with claim 1, wherein at least one diaphragm which bounds a flow cross-section for the coolant is provided in the coolant circuit (25).
 7. The pump in accordance with claim 6, wherein the at least one diaphragm is an adjustable diaphragm.
 8. The pump in accordance with claim 1, further comprising a temperature sensor (28) for measuring the temperature of the side passage pump stage (12).
 9. The pump in accordance with claim 8, wherein the temperature sensor (28) is arranged between the coolant passage (18) and the side passage (16).
 10. The pump in accordance with claim 8, wherein the temperature sensor (28) is arranged in the proximity of a gas outlet (36) of the side passage pump stage (12).
 11. The pump in accordance with claim 1, wherein the coolant passage (18) extends over at least approximately the total length of the side passage (12).
 12. The pump in accordance with claim 1, wherein the coolant passage further comprises at least one of a coolant inlet arranged in the proximity of a gas outlet (36) of the side passage pump stage (12) and a coolant outlet arranged in the proximity of a gas outlet (34) of the side passage pump stage (12).
 13. The pump in accordance with claim 1, wherein the pump (10) comprises a plurality of side passage pump stages (12) which each comprise a side passage (16) bounded by at least one stator element (14), wherein the coolant circuit (25) for the side passage pump stages (12) respectively comprises at least one coolant passage (18) and wherein the coolant passages (18) are each bounded by the stator element (14) which bounds the side passage (16) of the respective side passage pump stage (12).
 14. The pump in accordance with claim 13, wherein at least two coolant passages (18) of different side passage pump stages (12) are connected to one another in a coolant conducting manner in series or in parallel.
 15. The pump in accordance with claim 13, wherein at least two coolant passages (18) of different side passage pump stages (12) extend from their respective coolant inlet (30) in opposite directions about an axis of rotation (38) of the side passage pump stages (12) to their respective coolant outlet (32).
 16. The pump in accordance with claim 15, wherein the at least two coolant passages (18) of different side passage pump stages follow one another directly in the axial direction or in the radial direction.
 17. The pump in accordance with claim 13, wherein a return passage (40) of the coolant circuit (25) extends through a plurality of stator elements (14) which bound the side passages (16) of the side passage pump stages (12).
 18. The pump in accordance with claim 1, wherein the coolant circuit (25) is coupled in a heat exchanging manner via at least one heat conducting element (20) to a further coolant circuit (42).
 19. A pump having at least one side passage pump stage (12) which comprises a side passage (16) bounded by at least one stator element (14), having a motor (22), having drive electronics (20) for the motor (22) and having a coolant circuit (25) for cooling the pump (10) with a coolant, wherein the coolant circuit (25) comprises at least one first coolant passage (18) for the side passage pump stage (12) and at least one second coolant passage (26) for at least one of the motor (22) and the drive electronics (20).
 20. The pump in accordance with claim 13, wherein the first coolant passage (18) and the second coolant passage (26) are connected to one another in a coolant conducting manner in series or in parallel. 